1. Field of the Invention
The present invention relates to display devices and liquid crystal display devices each including a display screen constituted by a plurality of pixels. More specifically, the present invention relates to a multi-primary color display device which can be used for various displays such as a liquid crystal display, a PDP (Plasma Display Panel), an Organic EL (Electroluminescent), a FED (Field Emission Display) by constituting an image using multi-primary colors, and also relates to a liquid crystal display device comprising such a display device.
2. Description of the Related Art
As display devices, various displays forming an image by pixels have been widely used as means for displaying information or images. Display devices in which one pixel is constituted by sub-pixels of three colors of RGB and thereby color display is provided are common. In such a color display technology, it has been recently considered that a color reproduction range is enlarged for improvement in display quality. For example, increase in color purity of three primary colors of RGB enlarges the color reproduction range in a chromaticity diagram. In this case, however, the brightness is reduced due to the increase in color density. In addition, a method of enlarging the color reproduction range in a liquid crystal display and the like by increasing the number of sub-pixels using four or more primary colors has been proposed.
As a technology relating to enlargement of the color reproduction range in a conventional display device, a liquid crystal display device in which each pixel of red, blue, green, and white is arranged in the row direction, and in the column direction, pixels with the same color are arranged is disclosed (for example, referring to Japanese Kokai Publication No. 2004-102292, pages 1, 2, and 22). In this liquid crystal display device, a method of adding W to the RGB three primary colors, thereby improving the brightness and the color reproduction range is proposed. Two color arrays of stripe array and matrix array have been proposed. The stripe array is commonly adopted in application of large displays such as TV, because of matching property with images. FIG. 11 shows an embodiment of this stripe array in a liquid crystal display device. In this case, R, G, B, and W are arranged in this order to form one pixel. In such a configuration, the color reproduction range can be larger, but G and W are separately recognized when one white line is displayed on a dark background. A liquid crystal display device in which a fine filter forming a color filter has four colors corresponding to a R-G axis and a B-Y axis is disclosed (for example, referring to Japanese Kokai Publication No. 2001-209047 (pages 1, 2, and 6)). However, in this liquid crystal display device, there is no disclosure that the four-color array is the stripe array.
A method of increasing the number of sub-pixels to five, or six, thereby increasing the number of colors, in order to more improve the color reproduction range has been proposed. For example, a five color sub-pixel configuration having an array shown in FIG. 12 is disclosed (for example, WO 03/088203 (pages 1, and 10 in Drawings). In this configuration, the sub-pixels constituting one pixel are arrayed in hue order of RYGCB. In such a configuration, the color reproduction can be larger, but B/C and Y are separately recognized when one white line is displayed on a black background. Therefore, there is room for improvement in order to improve display quality by achieving enlargement of the color reproduction range and suppression of the brightness reduction.
With respect to a liquid crystal display device performing color display using sub-pixels of at least four primary colors, it is disclosed that five primary colors of RGYBC are arranged as four sub-pixels of RGYB, CRGY, BCRG, YBCR, or GYBC (for example, referring to WO 02/101644 (pages 1, 2, and 9 in Drawings)). Also disclosed are a plasma display panel including pixels constituted by discharge cells of red, green, blue, and blue green as four primary colors (for example, referring to Japanese Kokai Publication No. 2004-152737 (pages 1 and 2), and a liquid crystal panel including sub-pixels in 2×3 arrays using six colors, as shown in FIG. 14 (for example, referring to “SID sokuhou”, “online”, May 26, 2004, Nikkei Business Publications, Inc. However, these display devices also have room for improvement in order to sufficiently suppress color separation phenomenon and the like in white line display, and thereby to improve basic performances in displays such as liquid crystal TVs for which excellent display quality is needed.